This invention relates generally to the field of electromagnetic launchers, and more particularly to a light activated semiconductor switch device for use as a projectile/armature in a railgun.
Electromagnetic launchers or railguns are devices well known in the art and include a projectile or armature sliding between two parallel rails with the projectile/armature acting as a sliding switch or an electrical short between the rails. By passing a large current down one rail through the armature and back along the other rail or through a plasma arc behind the armature, a large magnetic field is built up behind the armature projectile accelerating it to a very high velocity by the Lorentz force generated behind the projectile/armature. Unlike conventional and light-gas guns, railguns employ an electromagnetic driving force and therefore can achieve projectile velocities which are not limited to the sonic velocity of a driving gas.
One of the main problems associated in the design of railgun systems, however, is the power supply and switching mechanism which must be able to supply large amounts of energy and high current levels, i.e. megamperes. Depending upon the particular application, the switch must operate at pulse repetition frequencies of many times a second, typically 50 pps. with rise times in the microsecond range.
Accordingly, it is an object of the present invention to provide an improvement in electromagnetic launchers.
It is another object of the invention to provide an electromagnetic launcher including a combined armature and switch mechanism.
It is a further object of the invention to provide an electromagnetic launcher which includes an expendable one shot armature/switch which operates at relatively high repetition rates.
It is yet another object of the invention to provide an electromagnetic launcher which includes a low cost yet reliable semiconductor switch type armature for tailoring the current profile flow through the armature.
And yet still another object of the invention is to provide an electromagnetic launcher including a semiconductor switch type projectile/armature which demonstrates reliability, high-power handling capability and which can provide variable current rise times and pulsewidths by controlling the intensity and time duration of a laser light beam.